Spring assisted sofa convertible into bunk bed

ABSTRACT

A sofa bed is convertible to a bunk bed using a base frame assembly; an upper bunk assembly to be disposed on the base frame assembly in a seating position and to be disposed above the base frame assembly in a bunk bed position; a front link and a rear link pivotally attached to the base frame assembly and the upper bunk assembly, alternative embodiments adding a flange plate secured to the rear link with a motor, cable, drive, screw and drive assembly, or adding a torsion spring assembly, or substituting vertical scissors mechanism for the links or substituting telescoping supports for the link assemblies.

CLAIM OF PRIORITY

This application is a Continuation In Part application based on application Ser. No. 15/361,340 filed Nov. 25, 2016 which parent application claims priority on Provisional application Ser. No. 62/259,956 filed Nov. 26, 2015, having attorney docket No. CU-72546, application Ser. No. 15/360,791 filed Nov. 23, 2016 having attorney docket number CU-72998 and application Ser. No. 15/361,340 Filed Nov. 25, 2016 having attorney docket number CU-72999, all having the same inventor as the present application.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to a furniture assembly, and more particularly, to a sofa bed convertible into a bunk bed having a mechanism being compact and particularly adaptable to placement in vehicles or dimensionally limited locations.

Background

A sofa usually has a seating surface, a back surface, and arms, while a bunk bed has a plurality of sleeping surfaces oriented with at least a portion of a top sleeping surface vertically displaced above a lower sleeping surface. The convertible bunk bed stores the bed in the area above the seating surface. In the prior art EP2110054 (A1) “Mechanism for bunk beds and sofa-bed comprising this mechanism” appears to use curved links to enable a bunk bed to be moved vertically to a position above the lower bed. In the prior art CN202553068 (U) “Novel dual-use sofa” the arms of the sofa are pivoted so that the top bunk is inverted when the sofa is in the seating position and when rotated 180 degrees upwardly so that the frame inverts to present the opposite surface for sleeping.

The former utilizes a mechanism of some complexity for ease of deployment, but lacks a desirable level of rigidity and support when in the bunk bed position. The latter requires a substantial range of motion for movement of significant mass in directions atypical to the user.

In the prior art U.S. Pat. No. 405,495 “Foldable Bunk Bed Assembly” a hinged outer portion of a seat back converts to upper bunk but requires mounting on a wall or bulkhead. U.S. Pat. No. 7,360,261 “Sofa” hinges the seat back to the seat back frame pivoting upward to a bunk bed position. U.S. Pat. No. 4,592,101, “Sofa-bunk bed combination with pivotable cushion” pivots and elevates the seat back to be used as the top bunk. Published application CN202553068U “Novel dual-use sofa” has a hinged front and rear portion with overlapping platforms in which the front portion rotates forwardly and upwardly and inverts, the upper inverted platform forming the bunk bed and the lower platform forming the lower bed. Published application EP2110054 (A1) “Mechanism for bunk beds and sofa-bed comprising this mechanism” uses complex linkage to raise and invert a lower seat platform so that when inverted and fully raised it forms a top bed in a bunk bed.

The present invention solves problems in the prior art described above. The sofa convertible to a bunk bed described herein provides superior sleeping surfaces in a more compact footprint and range of motion, while additionally providing structure for mounting in vehicles and clearance for mounting such securement apparatus as seat belts and harnesses over that of the prior art sofa bunk beds. Links acting in combination with pneumatic cylinders or other telescoping struts provide mechanical advantage and locking for a trussile support mechanism. The frame design additionally incorporates guards and ladders in a unitary assemblage.

Two main embodiments are shown, one with a front link having a pivot carried in a track and a second having fixed pivot for the front link. Each embodiment may have alternative embodiments within the teaching of the main embodiment.

Four improved embodiments are shown. A powered embodiment uses a single motor driving rotating threaded rods to move drive nuts mounted to each rear link. A torsion spring embodiment uses wound torsion springs to assist in raising the top bunk. A scissors vertical lift embodiment replaces the straight links with front and rear pivoted link assemblies. A telescoping vertical lift embodiment uses front and rear telescope assemblies

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 2 is a side elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 3 a perspective view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 4 is a front elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 5 is a side elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 6 is a top plan view of an embodiment of the sofa convertible to a bunk bed with the front guard undeployed.

FIG. 7 is a perspective view of an embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 8 is a perspective view of an embodiment of the sofa convertible to a bunk bed in the mid-position.

FIG. 9 is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 10 is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the mid-position.

FIG. 11 is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position taken on line A-A of FIG. 1.

FIG. 12 is a perspective view of an embodiment of the sofa with mattress and cushions shown.

FIG. 13 is a perspective view of an embodiment of the sofa with mattress and cushions shown with the bunk configured for sleeping.

FIG. 14 is a perspective view of an embodiment of the sofa back cushion. FIG. 1 is a front elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 15 is a side sectional view of an embodiment of the sofa taken on line A-A of FIG. 1 having a first alternative track and gas cylinder pivot location.

FIG. 16 is a side sectional view of an embodiment of the sofa taken on line A-A of FIG. 1 having a second alternative track and gas cylinder pivot location.

FIG. 17 is a side elevational view of an embodiment of the sofa taken on line A-A of FIG. 1 having a third alternative track and gas cylinder pivot location.

FIG. 18 is a side elevational view of an embodiment of the sofa taken on line A-A of FIG. 1 having a fourth alternative track and gas cylinder pivot location.

FIG. 19 is a front elevational view of another embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 20 is a side elevational view of another embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 21 a perspective view of another embodiment of the sofa convertible to a bunk bed in the bunk bed position.

FIG. 22 is a front elevational view of another embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 23 is a side elevational view of another embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 24 is a top plan view of an embodiment of the sofa convertible to a bunk bed with the front guard undeployed.

FIG. 25 is a perspective view of an embodiment of the sofa convertible to a bunk bed in the sofa position.

FIG. 26 is a perspective view of an embodiment of the sofa convertible to a bunk bed in the mid-position.

FIG. 27 is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the sofa position, taken on line A-A of FIG. 19.

FIG. 28 is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the mid-position.

FIG. 29 is a sectional elevational view of an embodiment of the sofa convertible to a bunk bed in the bunk bed position taken on line B-B of FIG. 19.

FIG. 30 is a fragmentary perspective view of the left side linkage assembly, looking from the rear towards the front.

FIG. 31 is a fragmentary perspective view of the right side linkage assembly, looking from the rear towards the front.

FIG. 32 is a sectional view of a powered variation on an alternative embodiment having a drive assembly acting on the front link.

FIG. 33 is a fragmentary sectional view of a lock mechanism

FIG. 34 is a perspective view of an embodiment in the bunk bed position.

FIG. 35 is a side sectional view of the powered embodiment.

FIG. 35 A is an enlargement of the gear box and drive arrangement of the powered embodiment from the side.

FIG. 36 is a front sectional view of the powered embodiment.

FIG. 36 A is an enlargement of the gear box and drive arrangement of the powered embodiment from the front.

FIG. 37 is a side sectional view of the torsion spring embodiment.

FIG. 37 A is an enlargement of the torsion spring arrangement of the torsion spring embodiment.

FIG. 37 B is an enlarged sectional view of the torsion spring arrangement of the torsion spring embodiment.

FIG. 38 is a front sectional view of the torsion embodiment.

FIG. 38 A is an enlarged sectional view of the torsion spring arrangement of the torsion spring embodiment.

FIG. 39 is a side sectional view of a scissors vertical lift embodiment.

FIG. 40 is a front sectional view of a scissors vertical lift embodiment.

FIG. 41 is a side sectional view of a telescoping vertical lift embodiment.

FIG. 42 is a front sectional view of a telescoping vertical lift embodiment.

FIG. 42A is a front sectional view of one telescoping vertical lift that is cable operated.

FIG. 42B is a front sectional view of one telescoping vertical lift that is screw operated.

FIG. 42C is a front sectional view of one telescoping vertical lift that is hydraulic or pneumatic.

FIG. 43 is a perspective view of the power embodiment.

FIG. 44 is a perspective view of the torsion spring embodiment.

FIG. 45 is a perspective view of the vertical scissors linkage embodiment.

FIG. 46 is a perspective view of the vertical telescoping embodiment.

Terms such as front, side, rear, left and right as may be used herein are relative terms referring to the sofa convertible to a bunk bed and are not limited to its mounting, installation or arrangement to any particular position or space in a room or vehicle or to which direction a person is oriented on the sofa or bed. Unless otherwise qualified left and right refer to the point of view of a person sitting on the sofa.

DETAILED DESCRIPTION

Referring to the drawings, the sofa bed 10 of this invention is generally shown. The sofa bed 10 includes base frame assembly 12 with side frames 14 and 16 interconnected by rear transverse frame 18 and front transverse frame 20. Side frames 14 and 16 may be formed of perimetrical frame members, solid plates 22, 24, or a combination. Each plate 22, 24 is formed and arranged so as to have an angled, straight tracks or guide slots 26, 28.

Advantages to using solid sheet or plate could include the substantial elimination of components requiring assembly; the ability to be formed through automated manufacturing means such as laser cutting or other appropriate machining, and the elimination of braces between the tracks or guide slots 26, 28 which can be more easily maintained in position by the presence of the solid web between them.

The upper bunk frame 30 is formed with a lower perimetrical frame 32 and a rear guardrail assembly 34. On each side is a side guard 36, 38.

Upper bunk frame 30, when deployed in the bunk bed position is primarily supported by right and left front links 40, 42 and right and left rear links 44, 46. The right and left front links 40, 42 are dynamically actuated and statically fixed (when locked) by right and left front cylinders, 48, 50. The right and left rear links 44, 46 are dynamically actuated and statically fixed (when locked) by right and left rear cylinders, 52, 54. Cylinders 48, 50, 52, 54 are preferably pneumatic cylinders but equivalents such as hydraulic cylinders, or spring, screw or rack and pinion mechanisms could be used to perform the function of assisting in raising bunk bed frame 30 and maintaining it in the bunk bed position 56.

Front brace and ladder assembly 60 is pivotally mounted to the front frame In the bunk bed position 56 ladder 58 is rotated to a vertical position and locked, front brace 60 is rotated to a vertical position and locked with locking mechanism 64. Front guard 62 is rotated to a vertical position and locked with locking mechanism 64. Extending upwardly from side frames 14 and 16 are tabs 66, 68. These may be formed with frame members or plate or a combination.

In an embodiment, here described with reference to left links 42, 46 and cylinders 50, 54, which are shown in the sectional views of FIGS. 10, 11 and 12, left front link 42 has a top pivot 70 and bottom pivot 72. Left rear link 46 has a top pivot 74 and a bottom pivot 76. Left front cylinder 48 has an upper pivot which is connected to the corresponding link and a lower cylinder pivot 82. Left rear cylinder 54 has an upper pivot 84 and a lower pivot 84. The relative terms top, bottom, upper and lower refer to the orientation of the components when in the bunk bed position.

Front link bottom pivot 72 is formed and arranged to slide in guide slot 28 thereby providing the range of motion needed to permit the upper bunk frame 30 to move vertically, while also remaining in a substantially horizontal orientation. Rear link bottom pivot 76 is mounted to tab 68 in a fixed location so as to permit link 46 to rotate about pivot 76. Front link top pivot 70 and rear link top pivot 74 are mounted in fixed front and rear locations on upper bunk frame 30.

Left front cylinder 48 is mounted with front cylinder lower pivot 82 in a fixed location on plate 22 and the front cylinder upper pivot connected at front link bottom pivot 72. As pivot 72 slides in angled slot 28, pivot 82 causes compression of cylinder 48. However, as bunk frame 30 is moved first upwardly and frontwardly and then continuing upwardly and rearwardly, cylinder 48 extends to aid in raising frame 30 to the bunk bed position 56. This movement works together with rear cylinder 52 and rear link 44 through mounting rear cylinder lower pivot 86 on tab 66 with rear cylinder upper pivot 84 mounted to the median portion of rear link 44. These references refer to the sectional views and the opposite side will be a mirror image of that shown and described.

As frame 30 is moved from the sofa position toward the mid position, left rear cylinder 54 compresses slightly, but as link 46 passes the axis of cylinder 54, then cylinder 54 urges link 46 upward toward bunk bed position 56. In bunk bed position 56 each of right and left front cylinders, 48, 50 and right and left rear cylinders, 52, and 54 may be locked. At this time the ladder 58 and brace 60 are also locked at lock mechanisms 64. The bed is converted to a sofa in substantially the reverse manner.

The geometry of links right and left front links 40, 42, right and left rear links 44, 46 and their respective front link top pivot 70 front link bottom pivot 72, rear link top pivot 74, rear link bottom pivot 76, front cylinder upper pivot 80, front cylinder lower pivot 82, rear cylinder upper pivot 84 and rear cylinder lower pivot 86 is such that manual deployment may be accomplished as described, while alternative cylinders and other actuators and controls could be utilized for automatic deployment.

The mattress 90 shown in FIGS. 3, 11, 12 and 13 and the cushions shown in FIGS. 12 and 13 can advantageously be arranged so that the mattress 90 remains in the same position, either under the frame 30 when in the sofa position or available for sleeping in the bunk bed position 56. Seat cushion 92 may be thick enough to serve as a top mattress on the top bunk, or seat back cushion 94 could be formed in a foldable manner and unfolded from the sofa seat back configuration to a sleeping configuration. Cushion 92 could remain and be combined with cushion 94 for double the thickness.

In the alternative embodiments shown in FIGS. 15, 16, 17 and 18 sectional views at section A-A of FIG. 1, different configurations of tracks and links provide properties that may be tailored to specifically desired performance relative to the movement, compactness, strength and mechanical rigidity, noting sofa bed 10 right side frame 14 solid plates 22 guide slot 28 right front link 40 right rear link 44, right front cylinders 48 and right rear cylinder, 54 generally formed and arranged as described above but with specific variations controlling the movement of the bunk bed assembly as it is raised and lowered. In FIG. 15 and FIG. 16 slot 28 has a lower straight portion, a forwardly curving intermediate portion and an upwardly curving upward portion. FIG. 16 has increased size component sections and reinforcing members on plate 22. FIGS. 17 and 18 have some of the components removed for clarity, but show slot 28 in different configurations. FIG. 17 shows slot 28 in a nearly vertical orientation, with a generally straight lower portion an intermediate curve and a generally straight upward portion. In FIG. 18 slot 28 has a near vertical lower portion a forwardly curving intermediate portion and a straight upper portion.

Two main embodiments are shown, one with a front link having a pivot carried in a track and a second having fixed pivot for the front link. In the second embodiment front and rear links each have a lower pivot fixed on the side frame.

In the embodiment illustrated in FIG. 19-22 sofa bed 10 has a base frame assembly 212 formed with side frames 214 and 216 interconnecting rear transverse frame 218 and front transverse frame 220. Side frames 214, 216 have rear pivot mounting members 222, 224 positioned near the rear and front pivot mounting members 226, 228 positioned near the front.

Upper bunk assembly 230 including perimetrical frame 232 has top rear guardrail assembly 234 projecting upwardly from the rear and top side frames 236, 238 at the side forming a bunk enclosed on the sides and rear, but with the front open when in the lowered, seating, position,

Pivotally connected to front pivot mounting members 226, 228 right and left front links 240, 242. Similarly, pivotally connected to pivot mounting members 222, 224 are right and left rear links 244, 246.

In the down, or seating position, the bunk bed frame 230 is secured to the base frame 212 through the interaction of a lock assembly. In the embodiment show, lock plate 248, engaged with lock plunger 250 engaging an aperture in plate 248. Plate 248 is angled such that engagement of plunger 250 is essentially perpendicular to plate 248 and to the direction of motion of the frame 230 as it is raised. Plunger 250 can be cable actuated being interconnected to lock release 251. Release 251 could be manually operated, pedal operated, electrically, pneumatically or hydraulically operated. Manual operation has advantages in the use of fewer and generally more reliable parts. Electrical operation, such as by a solenoid has advantages in the variable means for control whether by switch or data processing controller.

After release 251 is actuated, plunger 250 disengages plate 248 thereby permitting upper bunk frame 230 to be lifted with the assistance of right and left gas cylinders, 252, 254 to bunk bed position 256.

Ladder 258 is, in this embodiment, part of the right side of front brace frame 260. Frame 260 thus, has one ladder post at the right side and another post at the left side. Frame 260 is pivotally mounted to frame 212 so that it folds flat above mattress 290. When bunk frame 230 is fully raised, frame 260 is deployed to as to latch to frame 260 thereby providing fixed vertical support.

Front guard 262 is pivotally mounted to the front of frame 230 so that it can be stowed underneath when frame 230 is moved to and is in the sitting position, but can be rotated through substantially 270 degrees to provide a total of four guards around the perimeter of frame 230.

In particular, front link mounting strut 263 depends downwardly from frame 230 and in addition to providing structure to which front links 240, 242 are pivotally connected (there is a mounting strut 262 on each side of frame 230) additionally is structurally supportive of plate 248 and ladder locking mechanism 264. Mechanism 264 I the embodiment uses projecting ladder locking tabs 266 which receive frame rod 268. Other locking or other engagement mechanisms could also be used.

The movement of assembly 230 using links 240, 242, 244 and 245 is controlled as bunk 230 moves slightly frontwardly and upwardly and then slightly rearwardly into a substantially vertically inline location above frame 212. This is accomplished as links 240, 242, rotate around front link top pivot 270 and front link bottom pivot 272 and links 244, 245 rotate around rear link top pivot 274 and rear link bottom pivot 276.

Movement is additionally controlled by links 240, 242, 244 and 245 having front timing arms 278, 279 and rear timing arms 280, 281 projecting downwardly, and generally perpendicularly although at a slightly obtuse angle. Arms 278, 279, 280 and 281 are themselves interconnected by timing links 282 283 that coordinate the rotation of links 240, 242, 244 and 245 as bunk 230 is raised or lowered.

The interconnection links 240, 242, 244 and 245, arms 278, 279, 280, 281 timing links 282 283 and pivots 270, 272, 274 and 276 enables the use of cylinders 252, 254 connected at cylinder upper pivot 284 and cylinder lower pivot 286 (each side having said pivots) so as to urge bunk 230 upwardly and permit downward movement for stowing in the seating position.

Thus, a single gas cylinder 252, 254 on each side directly urges the rear link 244, 246 upward while resisting closing from a bunk position 256 to a seating position and the timing link and pivot arrangement transfers those forces to the entire linkage arrangement. Each link 244, 246 has a top pivot 274 (hidden in FIG. 28) the rear link top pivot 274 connected directly to the bunk 230 using appropriate reinforcement and mounting members.

The front link 240, 242 is connected to a front strut 263 depending downwardly from the bunk frame 230. Strut 263 may be advantageously mounted in cooperation with components enabling both upward locking of brace frame 260 at locking mechanism 264 and incorporating downward locking such as lock plate 248.

Each of the front 240, 242 and rear 244, 246 links has a timing connection arm 278, 279, 280, 281 and the front 278, 279 and rear 280, 281 timing connection arms are interconnected by a timing link 282, 283. As shown in FIG. 30, 31, fragmentary perspective views looking from the back toward the front at each back corner. Looking forwardly side frames 216, 214 support the lower portion of the linkage mechanism showing left and right rear links 246, 244 and left right front links 242, 240, pivotally mounted at front link bottom pivot 272L, 272R and rear link bottom pivot 276 L, 276 R respectively. It will be noted that rear links 244, 246 can be advantageously formed from channel thereby permitting left right and gas cylinders, 254, 252 to be mounted within the flanges of the channel. Additionally, timing arms 278, 279, 280, 281 can be similarly formed, permitting the outer flanges to abut timing link, 283, 282 while the inner flanges permit spacing for timing link pivots 283 P, 282 P thereby providing clearance for operation while providing a more broad bearing arrangement for pivots 283 P, 282 P. Pivot mounting members 222, 224, 226, 228 can be configured as generally “U” shaped brackets providing similarly spaced bearing surfaces for the respective pivots they receive. A crossbar 296 interconnects the ends of left and right rear links 246, 244. At the bottom of side frames 214, 216 appropriate members could be included such as flanges or braces 299 for mounting to a floor or deck.

Electric motor actuation could also be used as shown in FIG. 32. An electric motor 312 could drive cables 314, 316 that operate a threaded thrust assembly 318, 320 or a rack arrangement that moves thrust member 322 which bears on front arms 278, 279.

FIG. 34 shows an upholstered sofa 10 in bunk bed configuration. Right and left side frames 214 and 216 are upholstered as are top side frames 236, 238. Top rear guardrail assembly 234 is covered and can receive removable seat back cushions which provide back support when in the seating position, with greater sleep area when removed. Seat cushions 292 can function as a sleep surface or they could be replaced with a stored mattress. The platform which supports the seat cushions and mattress could be formed with grid systems, convoluted springs hybrid grid and coil systems or springs such as are taught in U.S. Pat. No. 9,103,397 the disclosure of which is incorporated by reference as if fully set forth herein.

The powered embodiment used a rear link modified with flange plates 450, 452, a drive motor 410 driving two drive cables 420, 422 that rotate two drive gear boxes 430, 432, that rotate two drive screws 441 moving link 246 up and down with drive nuts 442, 443 bearing against pivots 444, 446 in brackets 460. The powered embodiment uses many the same components as the embodiment described in FIGS. 27-34 including seat frame 230, front links, 240, 242, base 212, timing link 282, the ladder assembly 258, front guard 262 and rear timing tube 283T.

The drive screws will be attached to the plate 450, 452 modified rear link 246 functionally replacing the gas cylinders 252, 254. Automatic switches are placed to prevent the unit from over-traveling. Movement of this embodiment follows same travel path as the manual embodiment.

Powered Embodiment

FIG. 35 and FIG. 36 show a powered embodiment. The powered embodiment includes a base frame assembly 212; a upper bunk assembly 230 configured to be disposed on the base frame assembly 212 in a seating position and to be disposed above the base frame assembly 212 in a bunk bed position 256; a rear link 246 or 248 pivotally attached to the base frame assembly 212 and the upper bunk assembly 230; a flange plate 450 secured to the rear link 246 or 248; a drive nut 442 secured to the flange plate 450 and a drive motor 410 configured to provide power for the screw drive 440 to rotate.

The drive motor 410 rotates the screw drive 440 to move the rear link 246. Since the rear link 246 is pivotally fixed to the upper bunk assembly 230, the powered embodiment changes its mode from the sitting position to the bunk bed position 256 as the upper bunk assembly 230 moves upward out from the base frame assembly 212. The upper bunk assembly 230 moves along the trajectory of the rear link 246. Thus, the upper bunk assembly 230 moves forward and backward as the upper bunk assembly 230 moves upward. Also, the powered embodiment changes its mode from the bunk bed position 256 to the setting position as the upper bunk assembly 230 moves downward to fit with the base frame assembly 212. Since the upper bunk assembly 230 moves along the trajectory of the rear link 246, the upper bunk assembly 230 moves forward and backward as the upper bunk assembly 230 moves downward. The structures of base frame assembly 212 and the upper bunk assembly 230 may be the same as described above in FIGS. 26-34 with the exception of rear link 246 which has been adapted to receive the drive mechanism 440 and to receive and distribute the forces applied, as described more fully below.

A first end of the rear link 246 may be pivotally attached to the upper bunk assembly 230. The top pivot 274 of the rear link 246 may be disposed on a side of a seating frame in the upper bunk assembly 230 associated with the top side frame 238. The top pivot 274 may also be disposed about forty percent of the length of the side from the rear of the top rear guardrail assembly 234. However, it should be appreciated that the position of the pivot 272 may be disposed in a different place of the side. A second end of the rear link 246 may be pivotally attached to the base frame assembly 212. However, the second end of the rear link 246 may not be the very end of the rear link 246. The side frame 214 may have a rear pivot mounting member 222 positioned near the rear and the top of assembly 214. A timing arm 280 may be secured to the rear link 246 and pivotally attached at bottom pivot 276 to the base frame assembly 212. A rear end of the rear timing arm 280 may be secured to timing link 282 and the front end of the rear timing link 282 may be pivotally attached to front arm 279. It should be appreciated that the numbers of the rear link 246, the rear pivot mounting member, and the rear timing arm 280 correspond to a mirror image on the other side as described with respect to the other embodiments. Timing tube 283T interconnects link 246 to the corresponding link on the opposite side coaxial with piviot 276.

A flange plate 450 may be secured to the rear link 246. The flange plate may be more than one 450, 452 with one on either wall of link 246. The same may apply to the opposite side link 248. Thus, if two side frames 236, 238 have two rear links 246, 248, respectively, two rear links 246, 248 each have two flange plates 450, 452. The flange plate 450 pivotally supports drive nut 442. Use of two flange plates 450, 452 permits two bearing surfaces supporting drive nut 442 while a single flange plate would require a complex cantilevered pivotal connection. Top drive nut pivot 484 is generally spaced perpendicularly downwardly and forwardly from a point about one third the distance between the top and bottom pivots of the rear link 246 or 248. For example, on an arm with eighteen inch spacing between the top and bottom pivots 274, 276, the plate pivot perpendicular is spaced five inches from the lower pivot and one inch from the longitudinal center of the arm. While mathematically this is twenty eight percent it is believed that about a one to three ratio will provide the required movement so that the upper bunk assembly 230 will move from a lowered, seating position, to the bunk bed position. The flange plate 450 is formed as an irregular hexagon. A base and two short perpendicular legs about the arm. Two angled legs lead to a top (although the shape is essentially inverted) perpendicular to the base such that the center of the drive pivot is spaced about one inch from the centerline of the arm. The added strength and geometry of the drive plate enable the requisite movement of the entire assembly.

The proportions of plate 450 provide that the pivot location is enabled when plate 450 is disposed between the first end of the rear link 246 and the second end of the rear link 246 as shown. In an alternative the geometry of flange plate 450 locating drive nut 442 may be incorporated in a unitary rear link 246. A corresponding drive nut 443 is shown on the other side's link 248.

Drive nut 442 has an internal thread and receives a screw drive 440 which has an external thread. As the screw drive 440 is rotated by gear box 430, receiving cable 420 itself rotated by motor 410, the external thread moves along the rotating axis through the internal thread of the drive nut 442 attached with pivot 484 between flange plates 450, 452. The drive nut 442 moves toward an end pivot 444 of the screw drive 440 as the screw drive 440 is rotated in a clockwise direction by drive gear box 430, 432. This will retract from a bunk position to a seating position.

As viewed upwardly from the end pivot 444 of the screw drive 440 to the drive nut 442, the drive nut 442 moves upwardly from the end pivot 444 as the screw drive 440 rotates in a counter-clockwise direction bearing on nut 442 acting through pivot 484 on flanges 450, 452 raising link 246 and therefore raising the seat frame 230 to the bunk bed position 256.

Drive screw 440 has a mirror image drive screw 441 on the opposite side engaging drive nut 443 driven by gear box 432. For the screw drives 440, 441 to move in a parallel way to the side frame 214 or 216, a gear box bracket 460 may be fixed on the middle of the side frame 214 or 216 toward inside of the sofa 10. On the gear box bracket 460, the first end of the screw drive 440 is pivotally fixed on the gear box bracket 460 using a drive gear 430.

Synchronization of movement of the lift mechanisms is provided using drive motor 410 to rotate two drive cables 420, 422. Drive cables 420, 422 project sidewardly from motor 210 toward each base side frames 214, 216. Cables are used to have sufficient flexibility that they can bend upwardly, slightly rearwardly and then forwardly to engage drive gears 430, 432 which in turn rotate screw drives 440, 441 at the same rotational speed. As a result, two nut drives 442, 443 rotate at the same rotational speed to move links 246, 248 at the same speed. Since one drive motor 410 provides the same rotational power to two screw drives 440, 441, this drive mechanism provides economy, weight savings, energy efficiency and timing. This works in connection with timing links 282, 283 and timing tube 283T.

A switch 470 may be disposed in the location of the release 251 of the assembly in FIG. 21 is disposed. However, it should be appreciated that the switch 470 may be placed in a different place. For example, the switch 470 may be placed on one of the side frames 214, 216, or on the upper bunk assembly 230. The switch 470 is electrically connected to the drive motor 410 to switch the position of the upper bunk assembly: the sitting position or the bunk bed position. The switch 470 may be a toggle switch. However, it should be appreciated that the switch 470 may be a different type of switch which makes the sofa conveniently change its mode. For example, the switch may be, but not limited to, a slide switch, a push button switch, and a rotary switch.

Torsion Spring Embodiment

The torsion spring embodiment uses rear links connected to spirally wound torsion springs. Links 246, 248 are urged upwardly from the seat position to the bunk bed position 256 by wound springs 510, 512 located concentric to pivot 276, on brackets 522, 524, the springs 510, 512 unwinding as the links 246, 248 and frame 230 are moved upwardly. The torsion spring embodiment uses many the same components as the embodiment described in FIGS. 27-34 including seat frame 230, front links, 240, 242, base 212, timing link 282, the ladder assembly 258, front guard 262 and rear timing tube 283T. Release can be accomplished by the same release arrangement as the manual embodiment, or other lock and release apparatus. Movement of this embodiment follows same travel path as the manual embodiment.

FIG. 37 and FIG. 38 are a side sectional view and a front sectional view of the torsion spring embodiment, respectively. And FIGS. 37 A, 37 B and 38 A enlargements of the torsion spring assembly. The torsion spring embodiment includes a base frame assembly 212; supporting an upper bunk assembly 230 configured to be disposed on the base frame assembly 212 in a seating position and raised to a bunk bed position 256. Control of raising and lowering is accomplished using a pivoted rear link 246, 248 pivotally attached to the base frame assembly 212 and the upper bunk assembly 230 and front links, of the same arrangement as the manual embodiment. A spirally wound torsion spring 510, 512 is mounted between the rear link 246, 248 and a bracket 522, 524 on the base frame assembly 212 to store the gravitational force of the upper bunk assembly 230 when twisted. Spring 510, at its inner spiral end engages spacer bushing 514 so as to be fixed in bracket 522 and its outer spiral end engages pin 514. Spring 512 is in a mirror image arrangement.

In the seating position, the torsion springs 510, 512 are wound and have stored energy to provide torque. When the torsion spring embodiment changes its mode from the sitting position to the bunk bed position 256, the torsion spring unwinds and exerts a force or torque toward the bunk bed position. This force enables a person who operates the torsion spring embodiment to more easily move the upper bunk assembly 230 from the sitting position to the bunk bed position 256. The other structures of base frame assembly 212 and the upper bunk assembly 230 are substantially the same as described above in FIGS. 26-34.

The top pivot 274 may also be disposed about forty percent of the length of the side from the rear of the top rear guardrail assembly 234. However, it should be appreciated that the position of the pivot 272 may be disposed in a different place of the side. A second end of the rear link 246 may be pivotally attached to the base frame assembly 212. However, the second end of the rear link 246 may not be the very end of the rear link 246. The side frame 214 may have a rear pivot mounting bracket 522 positioned near the rear and the top of assembly 214. Bracket 522 is formed and arranged to support pivot 276 and house spring 512, including anchoring at 514, 516 and alignment of spring 512 for energy storage and release. A timing arm 280 is secured to the rear link 246 and pivotally attached at bottom pivot 276 to the base frame assembly 212. A rear end of the rear timing arm 280 may be secured to timing link 282 and the front end of the rear timing link 282 may be pivotally attached to front arm 276. It should be appreciated that the numbers of the rear link 246, the rear pivot mounting member, and the rear timing arm 280 correspond to a mirror image on the other side as described with respect to the other embodiments. As noted the mirror image structure is on the opposite side.

The lock and release system shown in FIG. 29-33 applies to the torsion spring embodiment in the same way.

Vertical Lift Scissors Linkage

The scissors linkage vertical lift embodiment uses a modified base frame 612 and a modified seat frame, 630. The seat frame 630 lifts vertically with two linkage and cylinder assemblies per side formed of top rear links 614, 616 connected to bottom rear links 618, 620 and top front links 622, 624 connected to bottom front links 626, 628. Top rear links 614, 616 are connected to bottom rear links 618, 620 at scissors pivots 632, 634. Front top link 622, 624 and front bottom link 626, 628 are pivotally interconnected at scissors pivots 636, 638. The front and rear scissors link assemblies are connected to top frame 630 at top pivots 640, 642 and to bottom frame assembly 612 at bottom pivots 644, 646.

Motive force is provided by right and left rear gas cylinders, 652, 654 and right and left front cylinders 658 and the corresponding front cylinder on the opposite side, connected to the respective links at cylinder link pivots 662, 664 and to base 612 at cylinder base pivots 666, 668. Cylinders 652, 654, 656, 658 could be replaced by screw and gearbox and motor and cable assemblies as shown and described with respect to the motorized embodiment.

There would be no forward movement of the seat frame 630 when being raised or lowered. The scissors-linkage-cylinder assemblies would substitute positioning and vertical movement obviating the need for the pivoted front, rear and the timing links.

Ladder assembly 258 and front guard 262 would be the same as previously described embodiments. The vertical, scissors embodiment uses the same release method with finger pull cable release but could use alternate releases as identified above.

FIG. 39 and FIG. 40 are a side sectional view and a front sectional view of the scissors vertical lift embodiment, respectively. The scissors vertical lift embodiment includes a base frame assembly 612; a upper bunk assembly 630 configured to be disposed on the base frame assembly 612 in a seating position and to be disposed above the base frame assembly 612 in a bunk bed position 256. The frames are modified in that pivots 632, 634, 636, 637 have different structure, geometry and location than the equivalent pivots in the other embodiments, so as to be adapted to the needs of the vertical lift arrangement, including different link dimensions and increased stability given the longer supporting structure.

The drive motor 410 in the powered embodiment shown in FIG. 35 and FIG. 36 may be adapted to the scissors linkage vertical lift embodiment. Instead of using cylinders 630 and 634, each flange plate would be secured to the bottom front link 624 and the bottom rear link 620. Each flange plate or paired flange plate assembly could a drive nut. A screw drive would pivotally attached to the bottom of the base frame assembly 612 in a location analogous to cylinder pivots 644, 646. The screw drive rotates in the inner thread of each drive nut and moves the bottom front link 642 and the bottom rear link 640. The screw drives would each be connected to a drive cable. The drive cables would be connected to a drive motor 410. Thus, a drive motor 410 could provide rotational power to four drive cables and four screw drives to move the upper bunk assembly 630.

Vertical Lift Telescoping Embodiment

FIG. 41 and FIG. 42 are a side and front elevation of a telescoping vertical lift embodiment, respectively. FIGS. 43 A, 43 B and 43 C show alternative mechanisms for deploying and retracting the telescoping vertical lift embodiment. The telescoping vertical lift embodiment includes a base frame assembly 712 which supports an upper bunk assembly 730 in a seating position movable vertically to a bunk bed position 756; and a plurality of telescoping supports 710, 712, 714 and the corresponding front support on the opposite side, 716.

To deploy the upper bunk assembly 730, the plurality of telescoping supports are located near the corners of assembly 730, namely two rear telescoping supports 710, 712 adjacent side frames 216, 214 and two front telescoping supports 714, 716 also adjacent side frames 216, 214, but at the front. To operatively move the upper bunk assembly 730 and enable that upper bunk assembly 730 to fit in the base frame assembly 712 each telescoping support 710, 712, 714 and 716 deploys vertically upwardly and retracts vertically downwardly. The supports 710, 712, 714 and 716 are shown having a base tube, a top tube and two intermediate tubes. This number provides sufficient clearance for the seat position and adequate extention for the deployed bunk bed position 756. Greater or fewer numbers could be used in keeping with the clearance and extension parameters. Telescoping lift may be accomplished in a variety of ways such as a cable, winch and sheave system, screw power, or pneumatic or hydraulic deployment. These are illustrated in FIGS. 43A, 43B and 43C respectively. Pneumatic or hydraulic cylinders in FIG. 43C are shown in the alternative.

The perspective views FIGS. 43, 44, 45 and 46 make clear the deployment of the respective links or telescoping tubes at all four corners of the upper bunk assembly. 

In accordance with the invention it is claimed:
 1. A sofa convertible into a bunk comprising: a base frame assembly; a upper bunk assembly configured to be disposed on said base frame assembly in a seating position and to be disposed above said base frame assembly in a bunk bed position; a rear link pivotally attached to said base frame assembly and said upper bunk assembly; a torsion spring mounted to said rear link and said base frame assembly to distribute the gravitational force of said upper bunk assembly to said base frame assembly; wherein a first end of said rear link is pivotally attached to said upper bunk assembly and a second end of said rear link is pivotally attached to said base frame assembly; a rear timing arm is secured to said rear link; a first end of said rear timing arm is secured to said second end of said rear link at a substantially right angle and said first end of said rear timing arm is pivotally attached to a timing link; a front link is pivotally attached to said base frame assembly and said upper bunk assembly; a first end of said front link is pivotally attached to said upper bunk assembly and a second end of said front link is pivotally attached to said base frame assembly; a front timing arm is secured to said front link; a first end of said front timing arm is secured proximate said second end of said front link at a substantially right angle and said first end of said front timing arm is pivotally attached to said timing link; said timing link is pivotally attached to said front timing arm and pivotally attached to said rear timing arm; a first end of said timing link is pivotally attached to a second end of said front timing arm and a second end of said timing link is pivotally attached to a second end of said rear timing arm; said timing link maintains said front timing arm and said rear timing arm in parallel so that said front link and said rear link to move in parallel; said torsion spring is mounted to said second end of said rear link and said torsion spring is twisted and has the most energy stored in said seating position; said front link, rear link and timing link forming a first link assembly on a first side; a second link assembly comprising a mirror image of said first link assembly is formed and arranged on a second said of said sofa a timing tube interconnecting said first link assembly and said second link assembly.
 2. A sofa convertible into a bunk comprising: a base frame assembly; a upper bunk assembly configured to be disposed on said base frame assembly in a seating position and to be disposed above said base frame assembly in a bunk bed position; a rear link pivotally attached to said base frame assembly and said upper bunk assembly; and a torsion spring mounted to said rear link and said base frame assembly to distribute the gravitational force of said upper bunk assembly to said base frame assembly.
 3. The sofa according to claim 2, wherein a first end of said rear link is pivotally attached to said upper bunk assembly and a second end of said rear link is pivotally attached to said base frame assembly.
 4. The sofa according to claim 3 further comprising a rear timing arm secured to said rear link.
 5. The sofa according to claim 4, wherein a first end of said rear timing arm is secured proximate said second end of said rear link at a substantially right angle and said first end of said rear timing arm is pivotally attached to a timing link.
 6. The sofa according to claim 5 further comprising a front link pivotally attached to said base frame assembly and said upper bunk assembly.
 7. The sofa according to claim 6, wherein a first end of said front link is pivotally attached to said upper bunk assembly and a second end of said front link is pivotally attached to said timing link.
 8. The sofa according to claim 7 further comprising a front timing arm secured to said front link and pivotally attached to said timing link.
 9. The sofa according to claim 8, wherein a first end of said front timing arm is secured proximate said second end of said front link at a substantially right angle and said first end of said front timing arm is pivotally attached to said timing link.
 10. The sofa according to claim 9 further comprising said a timing link pivotally attached to said front timing arm and pivotally attached to said rear timing arm.
 11. The sofa according to claim 10, wherein a first end of said timing link is pivotally attached to a second end of said front timing arm and a second end of said timing link is pivotally attached to a second end of said rear timing arm.
 12. The sofa according to claim 11, wherein said timing link maintains said front timing arm and said rear timing arm in parallel so that said front link and said rear link to move in parallel.
 13. A sofa convertible into a bunk comprising: a base frame assembly; a upper bunk assembly configured to be disposed on said base frame assembly in a seating position and to be disposed above said base frame assembly in a bunk bed position; a rear link pivotally attached to said base frame assembly and said upper bunk assembly; a torsion spring mounted to said rear link and said base frame assembly having a first end mounted to said base frame assembly and a second end mounted to said rear link, wherein said torsion spring is twisted and has the most energy stored in said seating position.
 14. The sofa according to claim 13, further comprising: a first end of said rear link is pivotally attached to said upper bunk assembly; a second end of said rear link is pivotally attached to said base frame assembly; a rear timing arm is secured proximate said second end of said rear link at a substantially right angle and said first end of said rear timing arm is pivotally attached to a timing link.
 15. The sofa according to claim 14, further comprising: a front link pivotally attached to said base frame assembly and said upper bunk assembly; a first end of said front link is pivotally attached to said upper bunk assembly and a second end of said front link is pivotally attached to said base frame assembly; a front timing arm secured to said front link and pivotally attached to said timing link; a first end of said front timing arm is secured proximate said second end of said front link at a substantially right angle and said first end of said front timing arm is pivotally attached to said timing link.
 16. The sofa according to claim 15, wherein said timing link maintains said front timing arm and said rear timing arm in parallel so that said front link and said rear link to move in parallel.
 17. The sofa according to claim 16, further comprising: said front link, rear link and timing link forming a first link assembly on a first side; a second link assembly comprising a mirror image of said first link assembly is formed and arranged on a second said of said sofa.
 18. The sofa according to claim 16, wherein an elongated timing interconnector is fixed to said first link assembly and said second link assembly. 